1. Field of the Invention
The present invention relates to a display device.
2. Description of the Related Art
A display device has a structure in which an element that controls a light is sandwiched between a pair of substrates. For example, in an organic electroluminescence display device, a counter substrate is stuck onto a TFT (thin film transistor) substrate so as to face an OLED (organic light-emitting diode) element portion disposed on the TFT substrate. In this structure, in order to ensure the reliability of the OLED element portion formed on the TFT substrate, a sealing film made of SiN or the like is formed on the OLED element, and further for the purpose of reducing a loss of light caused by internal reflection, the counter substrate is stuck onto the TFT substrate through a filler.
It is general that drops of the filler are put inside of a convex dam disposed in a periphery of the TFT substrate so as not to protrude outside the dam. In this situation, it is difficult to completely fill an inside of the dam structure with the filler without any space, and a problem that air bubbles remain arises. If the air bubbles enter a display area, a display of an image is affected by the air bubbles. JP 2007-233117 A and JP 2005-302740 A disclose a measure against the air bubbles in the filler.
JP 2007-233117 A discloses that a protrusion is formed with the use of a film stacked on the TFT substrate, to thereby prevent the air bubbles from being involved in the filler. However, since the protrusion is formed by the stacked film, a height of the protrusion is limited, resulting in such a problem that the effect of the protrusion is small.
JP 2005-302740 A has proposed a structure in which a convex portion corresponding to the dam is not continuously formed, but divided in corner portions to provide gaps, and the filler is intentionally protruded outside. However, since the protrusion of the filler causes a process of removing the protruded filler to increase, this structure is not practical.